Protected membrane roof system

ABSTRACT

A protected membrane roof system for installation on a roof decking comprising an upper insulation board having an upwardly-facing upper board top surface and an opposite downwardly-facing upper board bottom surface, a ballast material positioned over the upper insulation board, and at least one fastener assembly having a base seated beneath the upper board, a rod extending substantially vertically from the base of sufficient size so as to extend beyond the upper insulation board and the ballast material, and a cap engaged with the rod above the ballast material, whereby the wind uplift resistance of the protected membrane roof system is improved and scour of the ballast material is reduced by effectively anchoring the ballast material to the upper insulation board beneath the ballast material.

RELATED APPLICATIONS

This is a continuation-in-part application and so claims priority under35 U.S.C. § 120 and is entitled to the filing date of co-pending U.S.Non-Provisional application Ser. No. 15/450,149 filed Mar. 6, 2017, andentitled “Protected Membrane Roof System,” which itself claims priorityunder 35 U.S.C. § 120 and is entitled to the filing date of U.S.Non-Provisional application Ser. No. 14/775,275 filed Sep. 11, 2015, andentitled “Protected Membrane Roof System,” now U.S. Pat. No. 9,587,402,which is national stage entry under 35 U.S.C. § 371 of International PCTapplication Ser. No. PCT/US2014/024673 filed Mar. 12, 2014, and entitled“Protected Membrane Roof System,” which itself claims priority under 35U.S.C. § 120 and is entitled to the filing date of U.S. Non-Provisionalapplication Ser. No. 13/798,810 filed Mar. 13, 2013, and entitled“Protected Membrane Roof System,” now U.S. Pat. No. 8,863,442. Thecontents of the aforementioned applications are incorporated herein byreference.

INCORPORATION BY REFERENCE

Applicant(s) hereby incorporate herein by reference any and all patentsand published patent applications cited or referred to in thisapplication.

TECHNICAL FIELD

Aspects of this invention relate generally to roof systems andstructures, and more particularly to improved protected membrane roofsystems.

BACKGROUND ART

In general and for context, a protected membrane roof (“PMR”) isgenerally a typically flat or minimally sloped roof having one or morelayers of insulation (specifically extruded polystyrene) installed overthe waterproofing membrane and deck assembly. This configurationprovides for protection against UV radiation, thermal shock, theelements, and physical abuse for that vital waterproofing membranebelow. It is noted that conventional low-sloped roofs place the membraneon top of the insulation, while in “PMR” roof assemblies, thatwaterproofing membrane is typically placed directly on the structuraldeck (except for metal decks where a substrate board is installedfirst). In order to provide “ballasting” for the insulation and “PMR”roof system in general, some type of ballast material such as stones,pavers, or soil (garden roofs) or the like is applied over theinsulation layer(s) for further protection of the membrane as well asprotection effects for wind uplift resistance for the underlyinginsulation boards. To protect against scour of the ballast material, itis often preferable to apply a netting over the ballast material (i.e.,soil) and now to further expand that to other types of ballast such aspavers and stones. This netting which is applied over the ballastmaterial, either at least around a swatch of the roof perimeter or overthe entire roof, is then itself susceptible to wind uplift or beingblown off the roof even if staked within the ballast material. Toattempt to secure the netting against wind uplift, stakes or anchors aretypically applied to or secured within the ballast material itself. Oninformation and belief, the prior art anchoring approach, though perhapsrelatively easily installed and relatively inexpensive, results insignificantly reduced wind uplift resistance—on the order of only two tofour pounds (2-4 lbs).

What is needed is a protected membrane roof system wherein a fastenerassembly is secured beneath an insulation board thereof positionedbeneath the ballast material for improved wind uplift resistance.Aspects of the present invention fulfill these needs and provide furtherrelated advantages as described in the following summary.

DISCLOSURE OF INVENTION

Aspects of the present invention teach certain benefits in constructionand use which give rise to the exemplary advantages described below.

The present invention solves the problems described above by providing aprotected membrane roof system for installation on a roof deckingcomprising an upper insulation board having an upwardly-facing upperboard top surface and an opposite downwardly-facing upper board bottomsurface, a ballast material positioned over the upper insulation board,an optional netting positioned over the ballast material, and at leastone fastener assembly having a base seated substantially adjacent theupper board bottom surface, a rod extending substantially verticallyfrom the base of sufficient size so as to extend beyond the upperinsulation board, the ballast material, and the netting, if any, and acap engaged with the rod above the ballast material, whereby the winduplift resistance of the protected membrane roof system is improved andscour of the ballast material is reduced by effectively anchoring theballast material with or without netting to the upper insulation boardbeneath the ballast material.

A primary objective inherent in the above described apparatus and methodof use is to provide advantages not taught by the prior art.

Another objective is to provide such a system wherein any nettingpositioned over the ballast material is effectively anchored beneath theupper insulation board positioned beneath the ballast material.

Yet another objective is to provide such a system wherein any nettingpositioned over the ballast material is effectively anchored beneath thetop two insulation boards or between the top two and the bottominsulation board where three layers of insulation are employed.

Yet another objective is to provide such a system wherein the base ofthe fastener system for anchoring the ballast material and any nettingis substantially seated within a recess formed in the upper board bottomsurface.

Yet another objective is to provide such a system that enables variouspositioning of a waterproof membrane, including but not limited todirectly over the roof decking or between the upper insulation board andan adjacent lower insulation board positioned over the roof decking.

Yet another objective is to provide such a system that allows for avariety of ballast materials.

Yet another objective is to provide such a system that allows for acombination of ballast materials utilized together such as soil, stone,pavers, and/or insulation panels.

Yet another objective is to provide such a system that allows forsufficient ballasting of roof materials with or without the netting.

Yet another objective is to provide such a system that allows for theselective positioning of the fastener assembly within the upperinsulation board so as to extend between or through adjacent pavers orinsulation panels defining the ballast material.

Yet another objective is to provide such a system that allows forselection of the length of the rod of the fastener assembly to accountfor variations in the protected membrane roof system, particularly theone or more insulation boards and/or the ballast material.

Yet another objective is to provide such a system that allows forinstallation in conjunction with additional components, particularlyperimeter restraint components or systems.

Yet another objective is to provide such a system that allows forinstallation in stages while providing sufficient ballasting of roofmaterials at each stage.

And yet another objective is to provide such a system wherein apre-fabricated insulation board including an insulation layer having aninsulation layer top surface, a facer installed on the insulation layertop surface so as to be coterminous therewith, and at least onethrough-hole formed in the pre-fabricated insulation board so as to passthrough both the insulation layer and the facer may be employed, such asin substitution for the upper insulation board.

Other features and advantages of aspects of the present invention willbecome apparent from the following more detailed description, taken inconjunction with the accompanying drawings, which illustrate, by way ofexample, the principles of aspects of the invention.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings illustrate aspects of the present invention.In such drawings:

FIG. 1 is a perspective view of a first exemplary embodiment of aprotected membrane roof system according to aspects of the presentinvention;

FIG. 2 is an enlarged partial cross-sectional schematic of the firstexemplary embodiment thereof taken along line 2-2 of FIG. 1;

FIG. 3 is a further enlarged partial cross-sectional schematic takenfrom circle 3 of FIG. 2;

FIG. 4 is a cross-sectional schematic analogous to FIG. 2 of a secondexemplary embodiment;

FIG. 5 is a cross-sectional schematic analogous to FIG. 2 of a thirdexemplary embodiment;

FIG. 6 is a cross-sectional schematic analogous to FIG. 2 of a fourthexemplary embodiment;

FIG. 7 is a cross-sectional schematic analogous to FIG. 2 of a fifthexemplary embodiment;

FIG. 8 is a perspective view of an exemplary insulation board employedin a protected membrane roof system according to aspects of the presentinvention;

FIG. 9 is an enlarged partial cross-sectional schematic of the exemplaryinsulation board taken along line 9-9 of FIG. 8;

FIG. 10 is a cross-sectional schematic analogous to FIG. 2 of a sixthexemplary embodiment;

FIG. 11A is a cross-sectional schematic analogous to FIG. 2 of a seventhexemplary embodiment;

FIG. 11B is a cross-sectional schematic analogous to FIG. 2 of an eighthexemplary embodiment;

FIG. 11C is a cross-sectional schematic analogous to FIG. 2 of a ninthexemplary embodiment;

FIG. 11D is a cross-sectional schematic analogous to FIG. 2 of a tenthexemplary embodiment;

FIG. 12A is a cross-sectional schematic analogous to FIG. 2 of aneleventh exemplary embodiment;

FIG. 12B is a cross-sectional schematic analogous to FIG. 2 of a twelfthexemplary embodiment;

FIG. 13A is a cross-sectional schematic analogous to FIG. 2 of athirteenth exemplary embodiment;

FIG. 13B is a cross-sectional schematic analogous to FIG. 2 of afourteenth exemplary embodiment;

FIG. 14A is a cross-sectional schematic analogous to FIG. 2 of afifteenth exemplary embodiment;

FIG. 14B is a cross-sectional schematic analogous to FIG. 2 of asixteenth exemplary embodiment;

FIG. 14C is a cross-sectional schematic analogous to FIG. 2 of aseventeenth exemplary embodiment in a first operational mode;

FIG. 14D is a cross-sectional schematic of the exemplary embodiment ofFIG. 14C in a second operational mode;

FIG. 15 is a perspective view of a eighteenth exemplary embodiment of aprotected membrane roof system according to aspects of the presentinvention;

FIG. 16 is a perspective view of an nineteenth exemplary embodiment of aprotected membrane roof system according to aspects of the presentinvention;

FIG. 17A is a perspective view of a twentieth exemplary embodiment of aprotected membrane roof system according to aspects of the presentinvention;

FIG. 17B is a perspective view of a twenty-first exemplary embodiment ofa protected membrane roof system according to aspects of the presentinvention;

FIG. 17C is a perspective view of a twenty-second exemplary embodimentof a protected membrane roof system according to aspects of the presentinvention;

FIG. 18A is a cross-sectional schematic analogous to FIG. 2 of atwenty-third exemplary embodiment in a first operational mode; and

FIG. 18B is a cross-sectional schematic of the exemplary embodiment ofFIG. 18A in a second operational mode.

The above described drawing figures illustrate aspects of the inventionin at least one of its exemplary embodiments, which are further definedin detail in the following description. Features, elements, and aspectsof the invention that are referenced by the same numerals in differentfigures represent the same, equivalent, or similar features, elements,or aspects, in accordance with one or more embodiments.

MODES FOR CARRYING OUT THE INVENTION

The above described drawing figures illustrate aspects of the inventionin at least one of its exemplary embodiments, which are further definedin detail in the following description.

Turning now to FIG. 1, there is shown a “bird's eye” perspective view ofan exemplary embodiment of a protected membrane roof system 20 accordingto aspects of the present invention. As known in the art, a protectedmembrane roof (“PMR”) is generally a typically flat roof having one ormore layers of insulation installed over the waterproofing membrane forprotection against UV radiation, thermal shock, the elements, andphysical abuse, whereas conventional roofs have the waterproofingmembrane installed over the insulation leaving the membrane exposed tothe elements. In Protected Membrane Roofs, ballast material such assoil, stones, pavers, or the like is applied over the insulationlayer(s) for further insulation and protection effects as well as winduplift resistance for the underlying insulation boards. To protectagainst scour of the ballast material, it is often preferable to apply anetting over the ballast material, at least around a swatch of the roofperimeter or over the entire roof, which netting is then itselfsusceptible to wind uplift or being blown off the roof even if stakedwithin the ballast material. For further context, and again withreference to the illustrative protected membrane roof system 20, it isshown as being installed on a conventional flat-roofed office orindustrial building B. Such buildings are commonly formed with a parapetwall P about the perimeter of the roof of the building B, essentiallybeing an extension of the sides of the building B vertically beyond theroof decking R (FIGS. 2-7). Particularly in “garden roofs,” or roofsemploying vegetation and thus soil as the ballast material, the roofstypically also include vegetation free zones at the perimeters(typically 2′ to 4′ wide) where stone ballast or 2′×2′×2″ pavers Q areutilized. By way of illustration and not limitation, such pavers Q maybe manufactured by Hanover Architectural Products under the nameVentloc®. While such an illustrative type of PMR system is thusdescribed generally herein for context, it will be appreciated that theinvention is not so limited and may be employed in virtually any PMRsystem now known or later developed having ballast materials the scourof which is to be prevented.

With reference now to the enlarged cross-sectional schematic of FIG. 2,a first exemplary embodiment of the protected membrane roof system 20 isshown as generally comprising over the roof decking R, from bottom totop, a waterproofing membrane 50, a lower insulation board 40, an upperinsulation board 30, a drainage retention layer 60, a filter fabriclayer 62, soil ballast material 70, and netting 80. At least onefastener assembly 90 is provided for securing the netting 80 over thesoil ballast material 70 as described in greater detail further below.In the exemplary embodiment the joints 46 between adjacent boards 40 inthe same layer of insulation are to be staggered relative to the jointsin an adjacent insulation layer, such that the joints 46 in variouslayers are not substantially aligned. In the typical embodiment, theupper and lower insulation boards 30, 40 are formed of extrudedpolystyrene, typically two to six inches (2-6″) thick and serving toinsulate and provide dew point control, though it will be appreciatedthat virtually any insulation board now known or later developed assuitable for PMR systems generally, of virtually any material andthickness, may be employed in the present invention. It will beappreciated by those skilled in the art, with further reference to thealternative embodiments shown and described herein below, that whileparticular layered configurations of the exemplary protected membraneroof system 20 are shown and described, the invention is not so limited,but instead may involve more, fewer, or different layers in varyingorders within the construction without departing from the spirit andscope of the invention, such that the exemplary embodiment of FIG. 2 andthose further alternative embodiments of FIGS. 4-7 and 10-17 are to beunderstood as merely illustrative of aspects of the present invention.Specifically, and by way of further example, while soil ballast material70 is shown in FIG. 2, as well as FIGS. 10, 13A, 13B, and 17B, theinvention is not so limited, as stone ballast material 72 may beemployed as shown in FIGS. 4 and 5, paver ballast material 74 as shownin FIGS. 6 and 11A-11D, and insulation ballast material 76 as shown inFIGS. 7, 12A, and 12B, and thus the invention is not limited to any suchparticular ballast material but instead may involve any appropriateballast material now known or later developed. As will be appreciatedfrom further examples such as shown and described below in connectionwith FIGS. 17A-17C, combinations of ballast materials may be employed aswell. By way of further illustration and not limitation, as shown inFIGS. 14A-14D discussed below, a combination of soil ballast material 70and pre-cultivated vegetation mats 78 may also be employed. Once more,those skilled in the art will appreciate that the possible kinds andcombinations of ballast material employed in a protected membrane roofsystem 20 according to aspects of the present invention is virtuallylimitless.

With continued reference to FIG. 2 and further reference to the enlargedpartial cross-sectional schematic of FIG. 3, in the first exemplaryembodiment of the protected membrane roof system 20, once more, at leastone fastener assembly 90 is provided for securing the netting 80 overthe soil ballast material 70. More particularly, in the exemplaryembodiment, a base 92 of the fastener assembly 90 is positioned beneaththe upper insulation board 30, basically substantially trapped betweenthe upper board bottom surface 34 and the lower board top surface 42. Asshown, the base 92 is substantially embedded in the upper board bottomsurface 34 within a recess 38, though it will be appreciated that itcould potentially be embedded in the lower board top surface 42, or somecombination of the two, depending on the type of insulation materialemployed in each board 30, 40 and the treatment of any of the surfacesthereof, and thus how conforming the surfaces of each board 30, 40 mightbe, as well as the hardness, shape and thickness of the base 92 itself.As such, the recess 38 may be pre-formed in the upper board bottomsurface 34 or may be formed therein during the assembly of the protectedmembrane roof system 20 essentially by the compressive forces acting onthe system 20, again depending on the properties of the insulationboards 30, 40 and other factors. Or based on the relative flexibility ofthe insulation boards 30, 40 and/or the base 92 being sufficiently thin,no such recess 38 may be formed at all in some embodiments while stillallowing the fastener assembly 90 to be anchored beneath the upperinsulation board 30 and the insulation boards 30, 40 to still besubstantially flush upon installation. As such, those skilled in the artwill appreciate that the recess 38 may be formed, if at all, on a numberof surfaces or in a number of locations and through a variety of meanswithout departing from the spirit and scope of the invention. The base92 is configured having a rod 94 extending substantially verticallytherefrom, which rod 94 may be integral with the base 92 or removablyengaged therewith, more about which is said below in connection withalternate embodiments of the system 20. Wherever the fastener assembly90 is to be placed, and again whether or not a recess 38 is therepre-formed, as the base 92 is seated substantially against or adjacentthe upper board bottom surface 34, the rod 94 that extends from the base92 is to pass through the upper insulation board 30 and out its topsurface 32. It will be appreciated that such a through-hole 36 throughwhich the rod 94 passes may further be pre-formed, particularly when therecess 38 is already to be pre-formed, more about which is said below inconnection with FIGS. 8 and 9, or may be formed by drilling or othersuch forming technique “in the field” as the protected membrane roofsystem 20 is installed. As shown in FIGS. 2 and 3, with the base 92 andvertical fastener rod 94 so positioned beneath and passing through theupper insulation board 30, the rod 94 is configured to have sufficientlength to then extend through the ballast material 70 and verticallyabove the netting 80. As such, by forming a threaded portion 96 on thefree end of the rod 94, or opposite the base 92, a mating threaded cap98 may be threadably installed on the rod 94 so as to secure the netting80 over the ballast material 70. Accordingly, where additional layersabove the upper insulation board 30 such as the illustrated drainageretention layer 60 and filter fabric layer 62 are also employed in thesystem 20, the rod 94 must thus pass through such layers as well, withany necessary holes therein being formed in the normal course duringinstallation. In the exemplary embodiment, the base 92 of the fastenerassembly 90 is substantially annular with a nominal diameter ofapproximately six inches (6″), the rod is roughly one-quarter inch (¼″)diameter, and the threaded cap 98 is also substantially annular with anominal diameter of approximately four inches (4″). Such components maybe made of any suitable metal (e.g., steel or aluminum), plastic (e.g.,polyurethane or polyethylene), or other such material now known or laterdeveloped. It will be appreciated by those skilled in the art that anysuch fastener assemblies and components of any such geometricalconfiguration and material now known or later developed as suitable fora particular PMR context may be employed without departing from thespirit and scope of the invention. By way of further illustration andnot limitation, as expressly set forth below in connection with FIG. 4,while a threaded engagement between the rod 94 and the cap 98 is shownand described as by a threaded region 96 formed on the rod 94, theinvention is not so limited, but instead may involve a number of otherengagement or fastening means as part of the fastener assembly 90 nowknown or later developed without departing from the spirit and scope ofthe invention.

With further reference to FIGS. 1 and 2, in terms of the spacing of thefastener assemblies 90 within the overall protected membrane roof system20, it is noted that any roof system fastener spacing or density can beemployed with any ballast type depending on the building's wind exposureparameters and other factors. In an exemplary embodiment, it iscontemplated that one fastener 90 per two foot by eight foot (2′×8′)insulation board 30 would be sufficient, though closer spacing of thefasteners 90 (more fasteners per board) is possible to suit a particularapplication, as shown in FIGS. 1 and 2, or typically not every board 30would even have a fastener 90 as in other exemplary arrangementsdisclosed herein. Specifically, where two fasteners 90 are to beemployed per board 30, in the interest of having substantially evenspacing of the fasteners 90 throughout the system 20 and none of thefasteners too close to an edge of a board, the fasteners 90 would beabout four feet (4′) apart, or two feet (2′) from each short edge, so asto maintain the overall roughly four-foot spacing over the entire system20, even between fasteners 90 on adjacent boards. It will be appreciatedthat in some contexts even more fastener assemblies 90 per board 30 maybe employed and in some less, with not every board 30 even having afastener 30. Preferably all such fasteners 90 are located at least onefoot (1′) from any board edge, but this is not necessarily critical inall applications and certainly is not critical to the spirit and scopeof the present invention. Moreover, with the netting 80 typicallyprovided in nominal four-foot (4′) or eight-foot (8′) widths, suchfastener spacing enables alternate fasteners 90 to be positioned alongoverlapping seams between adjacent sections of netting 90, therebyhelping to further secure the netting 80 in position. Such netting 80 ascontemplated herein may be any suitable plastic, metal, or other suchnetting material now known or later developed and used in the art,including in some “garden roof” applications erosion control blankets(combination of woven plastic netting and coconut weave mesh or justmesh). In most cases, the netting 80 is utilized substantially from theroof edge to a point about eight feet (8′) inbound, while in other casessuch as the exemplary protected membrane roof system 20 shown in FIG. 1,the netting 80 is utilized over the entire roof. Those skilled in theart will appreciate that all such variations in the configuration of thenetting 80 and the number and positioning of the fastener assemblies 90are primarily dictated by the configuration of the building, includingits parapet, if any, the type of roof and ballast material to beemployed, applicable laws and regulations concerning wind upliftresistance requirements, the specifications of the owner or installer,and other factors, such that once more the exemplary protected membraneroof system 20 is to be understood as merely illustrative of featuresand aspects of the present invention and so is expressly non-limiting.On information and belief, a system 20 employed according to aspects ofthe present invention such as shown in FIGS. 1 and 2 may achieve winduplift resistance of two hundred pounds (200 lbs) or more when employedwith comparable ballast material 70, which in the case of soil can varyfrom typically four to eight inches (4-8″) in depth depending on theplants utilized and other factors, or thus from about fifteen totwenty-two pounds per square foot (15-22 lbs/ft²) installed. Thoseskilled in the art will thus appreciate that by installing the fastenerassemblies 90 beneath the upper insulation board 30 as shown in FIG. 2,and so taking advantage of the excellent flexural strength of the foamor other such material from which the insulation board 30 is formed,which boards typically have a thickness of at least two inches (2″), theforce to pull out the fastener assemblies 90 or otherwise tear or blowaway the netting 80, and thus the effective wind uplift resistance ofthe resulting overall protected membrane roof system 20 of the presentinvention is thereby greatly enhanced. Those skilled in the art willappreciate once more that all such dimensional and performance call-outsare merely illustrative of aspects of the protected membrane roof system20 of the present invention and are non-limiting, and as earlier statedall such schematic renderings shown in the figures are thus not to betaken literally or to scale, such that the thicknesses or depths of thevarious layers in the system 20 can vary widely beyond those shown anddescribed. By way of further illustration and not limitation, while atypical garden roof is shown and described as having a soil depth of onthe order of eight inches (8″) or less, often referred to as an“extensive” garden roof application, in other applications oftenreferred to as “intensive” the soil depth may be on the order of eightto twenty-four inches (8-24″) or more, again depending on a number offactors, wherein a protected membrane roof system 20 according toaspects of the present invention may be employed in conjunction with anyand all such garden roof configurations. Those skilled in the art willappreciate that where the soil or other ballast depth is increased andfastener assemblies 90 such as shown and described herein are employed,the rod 94 may simply be configured of sufficient length to extend asneeded through or above the ballast material such as soil 70 and anyoptional netting 80 that is employed.

Turning next to FIG. 4, there is shown a cross-sectional schematicanalogous to FIG. 2 of a second exemplary embodiment of the protectedmembrane roof system 20 of the present invention here employing a stoneballast material 72. As in the first exemplary embodiment of FIG. 2, theprotected membrane roof system 20 is shown as again generally comprisingover the roof decking R, from bottom to top, a waterproofing membrane50, a lower insulation board 40, an upper insulation board 30, a filterfabric layer 62, here stone ballast material 72, and netting 80, withthe drainage retention layer 60 (FIG. 2) here not being employed. An atleast one fastener assembly 90 is again provided having a base plate 92seated beneath the upper insulation board 30 with its rod 94 extendingupwardly therethrough and through the filter fabric layer 62 and thestone ballast material 72 and netting 80 for securing the netting 80thereover. It will be appreciated that in typical stone ballasted PMRsystems the layer of stone is not as thick as that of soil, renderingthe overall thickness of the system 20 in a stone ballast context not asgreat as with soil. However, even with the fastener assembly 90 seatedonce more in the same location within the system 20, namely, with thebase 92 between the upper and lower insulation boards 30, 40, it is yetdesirable that the retention cap 98 is still positioned substantiallyadjacent the netting 80 for proper securement. In one embodiment, then,the rod 94 may be selectively shortened to an overall length such thatthe cap 98 is properly positioned as by simply cutting or trimming therod 94 at a desired location, noting that the threaded portion 96 issufficiently long to accommodate such a shortening of the rod 94 andstill have threads remaining for engagement of the cap 98 in thatparticular exemplary method. Or, in an alternative embodiment, thefastener assemblies 90 may simply be produced with rods 94 of varyinglengths and the appropriate such fastener assemblies 90 selected for aparticular PMR installation ahead of time knowing the ballast materialthat is to be employed. Relatedly, where the base 92 and rod 94 areintegral, such effective sub-assemblies would be substituted dependingon the desired length of the rod 94; whereas, in a still furtherembodiment in which the base 92 and rod 94 are not integral, as by alsobeing threadably engaged, for example, it will be appreciated that rods94 of varying lengths can thus be substituted one for the other asneeded to suit a particular application. In a still further example, thesame fastener assemblies 90 may be employed for all jobs, including asingle rod length and, rather than being cut or trimmed, the engagementhole in the cap 98 may go completely therethrough so that the rods 94can do the same and the cap 98 thus be positioned at a wider variety ofheights along the rod 94. Relatedly, it will be appreciated by thoseskilled in the art that while particular rod 94 and cap 98configurations are shown and described herein as involving a threadedengagement, the invention is not so limited, but instead may involve anumber of other engagement or fastening means now known or laterdeveloped without departing from the spirit and scope of the invention.In the alternative illustrative embodiment wherein stone ballastmaterial 72 is employed, such may be selected, for example, as ASTM #5gradation, ASTM #4 gradation, or ASTM #2 gradation crushed stone orwashed riverbed stone applied at between ten and twenty pounds persquare foot (10-20 lbs/ft²), though once more it will be appreciatedthat a variety of other such ballast materials now know or laterdeveloped may be employed in the protected membrane roof system 20 ofthe present invention without departing from its spirit and scope.

Referring now briefly to FIG. 5, there is shown an alternate thirdembodiment similar to that of FIG. 4 wherein once again stone ballastmaterial 72 is employed in the protected membrane roof system 20.Essentially, the one difference is that the waterproof membrane 50 isnow positioned between the upper and lower insulation boards 30, 40rather than beneath the lower insulation board 40 immediately adjacentthe roof decking R as in the other embodiments herein. This is simply toillustrate as stated previously that the various layers within theoverall protected membrane roof system 20 may be changed, added orremoved without departing from the spirit and scope of the invention.For example, then, though a waterproof membrane 50 is now positionedbetween the upper and lower insulation boards 30, 40, a second suchmembrane 50 could still be positioned beneath the lower insulation board40 over the roof decking R as well—any such membranes may be the same ordifferent and single ply or multi-ply depending on the application.Moreover, it will be appreciated regarding placement of such a membrane50 between the insulation boards 30, 40 as shown in FIG. 5, orimmediately adjacent particularly the upper board bottom surface 34(FIG. 3), that by having the base 92 of the fastener assembly 90embedded within the upper board bottom surface 34 as by a pre-formedbottom recess 38 or otherwise, the base 92 is thus not likely tointerfere with, damage, or otherwise adversely affect the waterproofmembrane 50.

Turning next to the cross-sectional schematic view of FIG. 6, there isshown a fourth exemplary embodiment of the protected membrane roofsystem 20 of the present invention wherein now paver ballast material 74is employed. Here, the overall system 20 is otherwise analogous to theinitial stone ballast exemplary embodiment of FIG. 4 wherein thewaterproof membrane 50 is again directly over the roof decking R andthere is no drainage retention layer 60 (FIG. 2), though it will beappreciated once more that additionally or instead a single ply or othersuch membrane may be employed between the insulation boards 30, 40. Asshown in FIG. 6, each such paver 74 is to be positioned over the upperinsulation board 30 and any fabric filter 62 or other such optionallayer employed in the system 20 so as to be substantially square andabutting adjacent pavers 74, except that as also shown the fastenerassemblies 90 are to be positioned within the upper insulation board 30such that the rods 94 extend between adjacent pavers 74 rather thanhaving to pass through a paver 74. In the exemplary embodiment, thepavers 74 are formed of concrete and are roughly two foot by two footsquare and two inches thick (2′×2′×2″) so that it will be appreciatedthat with the typical four-foot (4′) or eight-foot (8′) spacing betweenfastener assemblies 90 they would thus be positioned each second orfourth paver 74, respectively. It will be further appreciated that anyother spacing of the fasteners 90 so long as in two-foot (2′) incrementswould accommodate the exemplary pavers 74 and position the fasteners 90therebetween, and further that a variety of other paver sizes may beemployed with the fasteners 90 simply spaced accordingly. It is alsonoted, though not shown, that pedestals may be placed beneath the pavers74 in any of the exemplary embodiments so as to space the pavers 74 fromthe underlying layers, including the upper insulation boards 30, and soprovide a gap for moisture venting; in the exemplary embodiments, suchpedestals or spacers may be on the order of three-sixteenth of an inch (3/16″), though it will be appreciated that such is illustrative andnon-limiting.

Referring now to FIG. 7, there is shown a cross-sectional schematic viewof a fifth exemplary embodiment of the protected membrane roof system 20wherein now a further insulation ballast material 76 is employed. Forpurposes of illustration, the overall system 20 is once again shown asin FIGS. 4 and 6 wherein the waterproof membrane 50 is directly over theroof decking R and there is no drainage retention layer 60 (FIG. 2),with the filter fabric 62, though still shown in FIG. 7, beingparticularly optional in conjunction with such insulation ballastmaterial or panels 76. Here, analogous to the fourth exemplaryembodiment of FIG. 6 wherein paver ballast material 74 is used, theinsulation ballast material 76 in the exemplary embodiment of FIG. 7 istwo foot by four foot (2′×4′) concrete-faced Styrofoam® insulation (suchas manufactured and sold under the name Lightguare), the panels 76having either a nominal two inch (2″) or three inch (3″) thickStyrofoam® insulation with a nominal three-eighths inch (⅜″) thick latexmodified concrete face, the details of which are not shown in FIG. 7 andare beyond the scope of the present invention. Again, virtually anycomparable panel or board now known or later developed may be employedso as to again be laid substantially square and abutting adjacent panels76 so as to serve as a ballast within the PMR system 20, with thefastener assemblies 90 once more preferably positioned within the upperinsulation board 30 such that the rods 94 extend between adjacentballasting panels 76 rather than having to pass through a panel 76.Here, with the panels 76 being a nominal two foot by four foot (2′×4′),it will again be appreciated that with the typical four-foot (4′) oreight-foot (8′) spacing between fastener assemblies 90 they would thusbe positioned between each panel or at each second or fourth panel 76,respectively, depending on the number and spacing of the fasteners 90and the orientation of the panels 76. It will be further appreciatedthat any other spacing of the fasteners 90 so long as in four-foot (4′)increments in one direction would accommodate the exemplary panels 76and position the fasteners 90 therebetween, it being noted that theexemplary Lightguard® insulation panels 76 are formed with tongue andgroove long edges, making it further preferable in that particularembodiment to space the fasteners at least every four feet (4′) in thepanel lengthwise direction so as to position them only along the shortedges thereof and so not interfere with the tongue-and-groove joints onthe long edges. Again, a variety of other panel or insulation boardsizes may be employed, with the fasteners 90 simply spaced accordingly.

With reference now to FIGS. 8 and 9, there is shown an exemplarypre-fabricated insulation board 100 according to aspects of the presentinvention having a basic insulation layer 102 formed of an extrudedpolystyrene foam or the like of a nominal two to six inch (2-6″)thickness; again, any appropriate material now known or later developedmay be employed in a variety of thicknesses without departing from thespirit and scope of the invention. In the illustrated embodiment, thepre-fabricated insulation board 100 is formed with two holes 110 toaccommodate fastener assemblies 90 such as shown in FIGS. 2-7 and 10-17,though again it will be appreciated that any number of fasteners 90 andthus holes 110 may be employed and that whether one or multiple holes110 are pre-formed in the insulation board 100, not all holes 110 needbe used in a particular roof system 20; accordingly, it will beappreciated that in other embodiments some such boards 100 may be formedwith holes 110 and some not, and in any case such holes 110 may bepre-formed in some or all boards 100 or may be formed on-site by theinstaller. With the exemplary board 100 having a nominal length L ofeight feet (8′) and a nominal width W of four feet (4′), the holes 110are thus positioned in the board 100 so as to be a distance D of twofeet (2′) from each long edge and from the respective short edge. As aresult, the two holes 110 on a single board 100 are substantially fourfeet (4′) apart as are each hole 110 from the closest hole on anadjacent board forming part of an overall protected membrane roof system20 according to aspects of the invention as shown in FIG. 1. In analternative embodiment, the pre-fabricated insulation board 100 has anominal length L of four to eight feet (4-8′) and a nominal width of twoto four feet (2-4′) so that one hole 110 to accommodate a singlefastener 90 may be formed in each board 100, though again those skilledin the art will appreciate that a variety of such prefabricated boards100 in terms of dimension and structure is possible according to aspectsof the present invention without departing from its spirit and scope.Furthermore, at the base of any through-hole 110, or in the insulationlayer bottom surface 106, a relatively larger diameter recess 112 may bepre-formed so as to accommodate the base 92 of a later-inserted fastenerassembly 90 as shown particularly in FIG. 3. It will be appreciated thatby pre-forming such through-hole 110 and optional recess 112 theinstallation of the boards 100 in the field, and particularly theinstallation of fastener assemblies 90 therewith, is made easier anderrors related to the proper spacing of the fasteners 90 are eliminated.As a further optional feature of the pre-fabricated insulation board100, a polyethylene facer 108 may be applied to the insulation layer topsurface 104 so as to then form the top side of the insulation board 100,though once more any other such material now known or later developedhaving suitable strength and water-resistance may optionally be employedwithin a pre-fabricated insulation board 100 according to aspects of thepresent invention. It will be appreciated by those skilled in the artthat such a pre-fabricated insulation board 100 may be substituted forthe upper insulation board 30 in any of the exemplary embodiments of theprotected membrane roof system 20 as shown in FIGS. 2-7 or in any othersuch PMR system according to aspects of the present invention withoutdeparting from its spirit and scope.

Turning to FIGS. 10-13, there are shown enlarged cross-sectionalschematics analogous to FIG. 2, here illustrating still furtherexemplary embodiments of the protected membrane roof system 20 accordingto aspects of the present invention, each of which it will beappreciated is further illustrative but non-limiting of the invention.More generally, those skilled in the art will again appreciate that avariety of configurations of the roof system 20 are possible accordingto aspects of the present invention, in terms of varying one or more ofthe ballast material, the insulation boards, the fasteners and netting,and other layers within the system 20, as dictated by a number of designand usage criteria, including but not limited to factors such asbuilding height and dimensions, including parapet dimensions, andclimate, including typical temperature range and wind conditions. First,a variety of other types and combinations of ballast materials may beemployed beyond those shown and described; that is, not only may otherballasts be employed and any of the ballast materials in varyingthicknesses, but combinations of such ballast materials may also beemployed together, as further illustrated in FIGS. 15 and 16. Second,the number and physical and geometric properties of any insulationboards employed in the roof system 20 may also vary depending on avariety of factors. While one, two, and three layers of insulationboards are illustrated, it will be appreciated that other numbers andthicknesses of such layers are possible according to aspects of thepresent invention without departing from its spirit and scope, even nolayers of insulation board apart from the ballast itself, more aboutwhich is said below. Third, a virtually infinite variety of fastener andnetting arrangements are possible, both in terms of the very presence ofthe netting, it being included in some systems 20 and not in others, andin terms of the placement of the fasteners anchoring the ballastmaterial, again, with or without any netting, in terms of the locationsof the fasteners relative to the ballast material and/or any insulationboards and relative to each other, as in fastener spacing or density,any and all of which again may vary depending on a number of factors.And fourth, other layers may be incorporated within (added to or removedfrom) the system 20 to suit particular applications, as might again bedictated by the building configuration, the geographical location, thekind of ballast material, etc. Once more, it will be appreciated bythose skilled in the art that a number of such arrangements are possibleaccording to aspects of the present invention without departing from itsspirit and scope, such that all exemplary embodiments shown anddescribed herein are to be understood as illustrative and non-limiting.

With reference now to the enlarged cross-sectional schematic of FIG. 10,a sixth exemplary embodiment of the protected membrane roof system 20 isshown as again generally comprising one or more layers of insulationboards 30 over a waterproofing membrane 50, a soil ballast 70 over theinsulation board(s) 30, and a netting 80 over the ballast 70 andanchored beneath the at least one insulation board 30. Morespecifically, here, over the roof decking R, the exemplary system 20entails, from bottom to top, a waterproofing membrane 50, a protectioncourse layer 64, which is effectively a second membrane, a root barrierlayer 66, a single layer of upper insulation boards 30, a drainageretention layer 60, a filter fabric layer 62, soil ballast material 70,and netting 80. Again, at least one fastener assembly 90 is provided forsecuring the netting 80 over the soil ballast material 70, the spacingof which is not to be taken literally or to scale from the schematic. Itwill thus be appreciated that in the alternative roof system 20 of FIG.10, such a “garden roof” with soil ballast 70 may be employed inrelatively warmer climates, thus enabling the use of a single insulationboard layer 30. The filter fabric layer 62 and drainage retention layer60 above the insulation board 30 provide protection from other elementssuch as moisture and even root growth from any plants placed within thesoil ballast 70 of the garden roof system 20 illustrated. As a furtherprotection, though, in the illustrated alternative embodiment, there isagain provided beneath the insulation board 30, or between the rest ofthe system and the membrane 50, the root barrier layer 66 and theprotection course layer 64, each of which serving as a furtherprotection for the waterproofing membrane 50 and thus the structurebeneath. Again, the protection course layer 64 serves as effectively asecond membrane—in the exemplary embodiment, the protection course 64 isa nominal 90 mil (0.090″) thick modified bitumen membrane—and the rootbarrier 66, as the name implies, serves to protect against furtherpenetration of any plant roots that may have grown through the soilballast 70 and the insulation board 30 and any other layers inbetween—in the exemplary embodiment, the root barrier 66 is a nominal 10mil (0.010″) thick polyethylene material; however, those skilled in theart will appreciate that the inclusion of such layers 64, 66 isoptional, and if any such layers 64, 66 are included they may be in anyorder or location, of any thickness, and/or of any material now known orlater developed. It will also be appreciated that such one or morelayers 64, 66 between the single layer of insulation boards 30 and thewaterproof membrane 50 serve to physically separate the fastener base 92from the membrane 50 and thus further protect the membrane 50 even asthe fastener 90 is anchored beneath the single insulation board 30. Oncemore, in the typical embodiment, the insulation boards 30 are formed ofextruded polystyrene, typically two to six inches (2-6″) thick andserving to insulate and provide dew point control, though it will againbe appreciated that virtually any insulation board now known or laterdeveloped as suitable for PMR systems generally, of virtually anymaterial and thickness, may be employed in the present invention.

Turning next to the cross-sectional views of FIGS. 11A-11D, there areshown four additional exemplary, related embodiments of the protectedmembrane roof system 20 according to aspects of the present invention,here each having as the ballast material a layer of pavers 74 over threelayers of insulation boards—a first layer of upper insulation boards 30and two abutting layers of lower insulation boards 40′, 40″. Asillustrated, the fastener assembly 90 is anchored beneath and passesthrough the top two layers of insulation boards—the upper insulationboard 30 and the second lower insulation board 40″. That is, what isconsidered the first lower insulation board 40′ is placed over thewaterproof membrane 50 and then the second lower insulation board 40″,or what is in the exemplary system 20 the intermediate insulation boardwithin the three layers, is placed over the first lower insulation board40′, between it and the upper insulation board 30. Accordingly, it isbetween the first and second lower insulation boards 40′, 40″ that thefastener base 92 is positioned, with the fastener rod 94 then passing upthrough the second lower insulation board 40″ and the upper insulationboard 30. It will be appreciated by those skilled in the art that thefastener assembly 90 could also just be anchored in the upper insulationboard 30 or could be anchored in all three insulation boards 30, 40′,40″ as by having the fastener base 92 beneath the first lower insulationboard 40′, between it and the membrane 50, depending on a number offactors related to the installation context. It will also be appreciatedthat while not shown, a variety of other membrane or other layers may beemployed between or adjacent to the various insulation boards 30, 40′,40″, and once more, any number of such insulation board layers may alsobe employed, as may be dictated by their thicknesses along with thecommercial application, the three boards shown being understood asillustrative and non-limiting; it will be further appreciated that herea system 20 as in the illustrated embodiment having three layers ofinsulation boards 30, 40′, 40″ may be employed in a commercialapplication in a relatively colder climate, for example. As shown inFIG. 11A, the fastener rod 94, upon passing through the upper insulationboard 30, is here positioned as passing between adjacent pavers 94 thatotherwise abut to form the ballast material layer of the roof system 90,with the fastener cap 98 then threadably or otherwise installed on therod 94 so as to span the edges of adjacent pavers 74. Whether or not thepavers 74 are in any way interlocking, it will be appreciated that byperiodically anchoring one or more pavers 74 of the ballast layer withinat least one layer of insulation boards 30, 40′, 40″ the overall winduplift resistance of the system 20 is improved, in that byintermittently fixing the positions of pavers 74 within the layer, therelative abutting positions of the remaining pavers 74 are in that sensefixed as well. Similarly, in FIG. 11B, each fastener assembly 90, androd 94 specifically, may instead pass through a hole formed in arespective paver 74, or basically through the body of a single paver 74rather than through the joint or gap between adjacent pavers 74, itbeing appreciated that such a gap results, in part, due to the presenceof the fastener rod 94. Accordingly, it will be further appreciated thatby passing the fastener rods 94 intermittently through various ones ofthe pavers 74, all pavers 74 in the ballast layer may thus be directlyabutting as shown, further fixing the relative locations within theballast layer of all pavers 74 even while only fastening some of thepavers 74. Those skilled in the art will appreciate that depending onthe application, the fastener density or spacing can vary widely, fromhaving a fastener in every or every other paver 74 or joint to a moreinfrequent distribution. And as will be explained further belowparticularly in connection with FIG. 16A, the fastener density can varyeven throughout a single roof system 20, such as having a relativelyhigher fastener density around the perimeter of the system 20 and arelatively lower fastener density throughout the middle of the system20. And with reference to FIGS. 11A and 11B together, it will beappreciated in the exemplary embodiments this anchoring of the paverballast material 74 is shown here as being accomplished without netting,the fastener caps 98 simply being positioned directly over the pavers74. Alternatively, with reference to FIGS. 11C and 11D, there are shownfurther exemplary embodiments analogous to FIGS. 11A and 11B,respectively, here further including a netting 80 over the ballastlayer, here of pavers 74, such that the netting 80 is trapped betweenthe pavers 74 and the fastener caps 98. It will be appreciated that byfurther tying the system together with the netting 80, wind upliftresistance is all the more improved, as the netting 80 would serve tofurther restrain both upward movement of any paver 74 and lateralmovement of any paver 74 relative to another essentially “from above”even as such lateral movement is restrained “from below” by anchoringthe fastener assembly 90, and the fastener rod 94 specifically, withinthe one or more layers of insulation boards 30, 40′, 40″. Those skilledin the art will appreciate in connection with the exemplary embodimentsof FIGS. 11A-11D that while pavers 74 of a uniform size or dimension areillustrated, a variety of other ballast materials of various sizes andshapes, again whether interlocking or free-floating or abutting, may beemployed within a protected membrane roof system 20 according to aspectsof the present invention without departing from its spirit and scope. Byway of illustration and not limitation, such pavers 74 may be thosemanufactured by Hanover Architectural Products under the name Ventloc®,having nominal dimensions of one foot by one-and-a-half feet and twoinches thick (1′×1½′×2″) (or, more precisely 11¾″×17⅝″×2″).

Referring next to FIGS. 12A and 12B, there are shown furthercross-sectional schematic views of alternative exemplary embodiments ofthe protected membrane roof system 20, here with interlocking insulationpanels 76 as the ballast above a single layer of insulation boards 30applied directly over the membrane 50, such as where the climate orother aspects of the commercial application allow for relatively lessinsulation. In a bit more detail, in FIG. 12A there is shown anexemplary system 20 comprising, from bottom to top, a waterproofingmembrane 50, an upper insulation board layer 30, and a layer ofinsulation panels 76, with at least one fastener assembly 90 anchoredwithin the upper insulation board 30 and passing through one of theinsulation panels 76 at an intermediate location. It will be appreciatedthat by virtue of the ballast insulation panels 76 interlocking and thenanchoring such panels 76 intermittently to the insulation boards 30below, the overall system 20 is relatively more secured or hasrelatively greater wind uplift resistance, as the spaced-apart fasteners90 serve to both maintain the relative positions of the panels 76, as bypreventing or minimizing relative lateral movement therebetween, and tomaintain the vertical position or prevent upward movement of theanchored panel 76, and thereby of the whole ballast layer due to thepanels 76 interlocking, though it will be appreciated that suchadvantage is achieved even if the panels are not interlocking, as notedabove in connection with the alternative embodiments involving abuttingpavers 74 as the ballast material layer as shown in FIGS. 11A-11D.Though it will be further appreciated that by interlocking the pavers 74or panels 76 or any other such ballast material relatively greater winduplift resistance may be achieved, all else being equal. Or, put anotherway, to achieve effectively the same or similar wind uplift resistancefewer fasteners 90 or a reduced fastener density could be employed in aninterlocking ballast context relative to a system wherein the ballastpavers or panels or other such ballast do not interlock. Moreover, asdiscussed above in connection with the particular alternativeembodiments of FIGS. 11C and 11D in the paver 74 context, here in theinsulation panel 76 context as shown in FIG. 12B, netting 80 may againbe provided over the insulation panel ballast layer 76 as trappedbetween the panels 76 and the fastener caps 98. It will be appreciatedthat by further tying the system together with the netting 80, winduplift resistance is all the more improved, as the netting 80 wouldserve to further restrain both upward movement of any panel 76 andlateral movement of any panel 76 relative to another essentially “fromabove” even as such lateral movement is restrained “from below” byanchoring the fastener assembly 90, and the fastener rod 94specifically, within the one or more layers of insulation boards 30.Relatedly, it will again be appreciated that any such arrangement, withor without netting 80, may be employed in further alternativeembodiments including additional or different layers of insulation andother protective layers as herein described, such that the exemplaryembodiments shown and described in connection with FIGS. 12A and 12B areto be understood as merely illustrative and non-limiting. Furthermore,in an alternative exemplary embodiment similar to that shown in FIG.12B, the layer of insulation boards 30 may be removed altogether suchthat the insulation panels 76 are applied directly over the membrane 50and thus serve as both the insulation and the ballast, with thefasteners 90 being anchored within the panels 76 themselves or only andthereby still securing the netting 80 snugly over the layer ofinsulation panels 76 to maintain the relative vertical and laterpositions of the panels 76 and thus the overall system 20 against winduplift, the netting 80 essentially tying the layer of panels 76 togetherin their abutting or interlocking arrangement and creating a moreintegral “whole.” By way of further illustration and not limitation, itis again noted that the insulation ballast material 76 in the exemplaryembodiments here of FIGS. 12A and 12B is two foot by four foot (2′×4′)concrete-faced Styrofoam® insulation such as manufactured and sold underthe name Lightguard®, the panels 76 having a nominal two inch (2″),two-and-a-half inch (2½″), or three inch (3″) thick Styrofoam®insulation with a nominal three-eighths inch to five-eighths inch (⅜-⅝″) thick latex modified concrete face. Such Lightguard® panels 76 aremost commonly configured to interlock, as with tongue-and-groove-typejoints, along their long edges and simply abut along their short edges.From the foregoing it will be appreciated that anchoring such a systemof insulation panels 76 at least within one or more insulation boards 30beneath and/or with a netting 80 above and thereby substantiallysecuring their relative lateral positions thus serves to better securethe overall ballast layer against wind uplift. And once more, any sucharrangement of panels of any size or configuration and with any relatedarrangement of the rest of the system 20 and particularly the fasteners90, in terms of locations and densities or spacing, and with or withoutany netting 80, are possible according to aspects of the presentinvention without departing from its spirit and scope.

In still further alternative exemplary embodiments, referring now toFIGS. 13A and 13B, there are shown cross-sectional schematic views of aprotected membrane roof system 20 according to aspects of the presentinvention again configured as a “garden roof” with soil ballast 70similar to the exemplary embodiment of FIG. 10, only here comprising aspart of the ballast layer an arrangement of one or more growth mediagrids 82 (special pavers with voids) for retaining the soil 70 and tohelp ballast the roof and any other plants A placed within the soil 70.Such growth media grids 82 may be interlocking or abutting in the regionof the vertical grid walls 84 in a manner known or developed in the art.In a bit more detail, then, in the exemplary arrangement of the system20 illustrated in FIG. 13A, from bottom to top, the system 20 includes awaterproofing membrane 50 installed over the roof decking R, theoptional protection course layer 64 and root barrier layer 66, at leastone upper insulation board 30, a drainage retention layer 60, a filterfabric layer 62, the soil ballast 70 contained within a layer of growthmedia grids 82, and a netting 80 over the soil ballast 70 and grids 82as anchored by one or fasteners 90 seated within or beneath the one ormore upper insulation boards 30. Here, the fastener assemblies 90, andparticularly the rods 94 thereof, are shown as abutting or beingproximate to the vertical walls 84 of the grids 82, with the fastenercaps 98 then seating thereover to retain the netting 80 in positionessentially over the soil 70 along the tops of the grids 82, or the gridwalls 84 specifically. Whether or not the grids 82 are formed withbottom walls (not shown) and whether or not such walls are solid orperforated or otherwise formed with holes or openings, such may beformed as necessary and the fastener rod 94 otherwise passed up throughthe grids 82 and soil 70 to as to be capped and retain or anchor thenetting 80 has herein described. Similarly, as shown in FIG. 13B, a“garden roof” system 20 analogous to that of FIG. 13A is shown, exceptthat here the fasteners 90 simply come up through an intermediatelocation within the growth media grids 82 and there fasten to or anchorover the netting 80. Either way, it will be appreciated by those skilledin the art that the netting 80 being anchored over the soil ballastlayer 80 at intermittent locations serves to secure such ballastmaterial against wind uplift and scatter, as further assisted byincorporation of the grids 82 and effectively tying both the grids 82and netting 80 to the insulation boards 30 beneath through spaced-apartfasteners 90. It will be further appreciated that plants A then plantedin or growing out of the soil 80 and up through the netting 80 furtherserve to anchor and tie the whole system 20 together as somewhat of amonolithic whole. Once more, those skilled in the art will appreciatethat a variety of other arrangements, including adding or removing orrearranging layers within the system 20 and employing various grids 82or other such devices in conjunction with the soil 70 are possibleaccording to aspects of the present invention without departing from itsspirit and scope, such that the illustrated embodiments are to beunderstood as exemplary and non-limiting. By way of further illustrationand not limitation, exemplary growth media grids 82 as may be employedin a roof system 20 according to aspects of the present invention,including those embodiments illustrated schematically in FIGS. 13A and13B, may be those provided by EcoGrid in the U.K. under the name EcoGridor provided by Hastings Architectural Products under the name CheckerBlock®. Also illustrative are the plants A shown as grass or other suchgrowth or groundcover, while it will be appreciated that a virtuallyinfinite variety of plants A may be planted or grown in the soil ballast70 depending on a number of factors, including but not limited to theclimate and the soil depth.

In yet further alternative exemplary embodiments, referring now to FIGS.14A and 14B, there are shown cross-sectional schematic views of aprotected membrane roof system 20 according to aspects of the presentinvention again configured as a “garden roof” with soil ballast 70, heresimilar to the exemplary embodiment of FIG. 10 but now comprising aspart of the ballast layer a pre-cultivated vegetation mat ballastmaterial 78 applied over the soil ballast material 70. With referencefirst to FIG. 14A, the protected membrane roof system 20 is shown asagain generally comprising one or more layers of insulation boards 30over a waterproofing membrane 50 and a soil ballast 70 over and anchoredbeneath the at least one insulation board 30. More specifically, overthe roof decking R, the exemplary system 20 entails, from bottom to top,a waterproofing membrane 50, a protection course layer 64, which iseffectively a second membrane, a root barrier layer 66, a single layerof upper insulation boards 30, a drainage retention layer 60, a filterfabric layer 62, soil ballast material 70, and here the vegetation mat78. Notably, the vegetation mat 78 may be any such mat, blanket, or thelike now known or later developed in the art, which typically comprisessome form of woven carrier, such as fabric, fiber (e.g., coir), etc.planted or seeded with a pre-cultivated variety of sedum-moss vegetationand/or grasses, herbs, wildflowers, host or nectar plants, etc. Thecarrier may be biodegradable or non-biodegradable, though it will beappreciated by those skilled in the art that a non-biodegradable carriermay add integrity to the vegetation mat ballast material 78 before,during, and after installation. A non-biodegradable carrier may haverelatively high tensile strength for handling during installation, whichmats 78 may be rolled out or laid and manipulated and potentially pulledtaut or cut and even tied together to form the desired top layer of thegarden roof system 20. And again, at least one fastener assembly 90 isprovided within the system 20 protruding up through the soil 70 here forthen securing the vegetation mat ballast material 78 over the soilballast material 70, the spacing of which fasteners 90 is again not tobe taken literally or to scale from the schematic, just as aren't thethicknesses of the soil and vegetation mat layers 70, 78, which may varywidely based on a number of factors. It will be appreciated that theunderlying soil ballast 70 supports further growth and rootestablishment of the vegetation on the overlying mat 78, eventuallytying the system together over time through such further growth oforganic material. Ultimately, the fasteners 90 are thus anchored belowin the at least one insulation board 30 as by the fastener base 92 andabove the vegetation mat 78 over the soil 70 as by the cap 98, the mat78 thus effectively functioning as or potentially replacing the netting80 as in FIG. 14A, particularly again where the woven carrier within themat 78 is non-biodegradable or essentially permanent. Briefly referringto FIG. 14B, whether or not the vegetation mat 78 has anon-biodegradable carrier, a netting 80 may still be applied over thevegetation mat 78, or between the mat 78 and the anchor cap 98 tofurther secure the entire garden roof ballast, once more depending on anumber of factors, including but not limited to the type of vegetation,the design characteristics of the roof, and the location of thebuilding. Once more, the alternative roof system 20 of FIGS. 14A and 14Byields a “garden roof” with soil ballast 70 and vegetation mat 78 thatmay be employed in relatively warmer climates, though not necessarilyso, thus enabling the use of a single insulation board layer 30, thoughagain two or more layers of insulation may be employed, and thefasteners 90 may engage or be employed with any number of suchinsulation layers. The filter fabric layer 62 and drainage retentionlayer 60 above the insulation board 30 provide protection from otherelements such as moisture and even root growth from any plantsoriginating on the mats 78 or otherwise placed or growing within thesoil ballast 70 of the garden roof system 20 illustrated. As a furtherprotection, though, in the illustrated alternative embodiment, there isagain provided beneath the insulation board 30, or between the rest ofthe system and the membrane 50, the root barrier layer 66 and theprotection course layer 64, each of which serving as a furtherprotection for the waterproofing membrane 50 and thus the structurebeneath. However, those skilled in the art will appreciate that theinclusion of all such layers 60, 62, 64, 66 is optional as is theirarrangement, such that a virtually infinite variety of systems 20involved one or more of any such layers and insulation boards, ofvirtually any material and thickness, may be employed in the presentinvention without departing from its spirit and scope, such that theillustrated embodiments are again expressly to be understood asexemplary and non-limiting.

Briefly regarding FIGS. 14C and 14D, there is shown a still furtherexemplary protected membrane roof system 20 according to aspects of thepresent invention again configured as a “garden roof” with soil ballast70 and a pre-cultivated vegetation mat ballast material 78 applied overthe soil ballast material 70 similar to that of FIGS. 14A and 14B, onlyhere illustrating a scenario where such ballast is applied or installedin stages or steps or in two operational modes. First, as shown in FIG.14C, the “garden roof” system 20 is initially formed much like that ofFIG. 10 as having soil 70 but not yet the vegetation mat 78. As apractical matter, there may be occasions where the protected membraneroof system 20 is installed to the point of applying the soil ballast 70over the rest of the system, but for reasons related to scheduling orthe time of year or season or the current weather, the vegetation mat 78may not be ready for installation or yet installed over the soil 70 Insuch a case, it may be beneficial to install a netting 80 over the soilballast 70, with first caps 98′ of the fasteners 90 then threadably orotherwise secured on or about the rods 94 so as to secure the netting 80over the soil 70. Where each first cap 98′ is to be threadably engagedwith the rod 94, it will be appreciated that the threaded portion 96 ofthe rod 94 may thus extend substantially along its entire length, or atleast along a greater and/or lower section of its length; it will alsobe appreciated that such first cap 98′ is to have a through-holeallowing for complete passage therethrough of the rod 94, while thesecond cap 98″ as described further below and consistent with the caps98 shown generally in the other exemplary embodiments need notnecessarily have a through-hole, though still might, both for the sakeof convenience in terms of inventorying only kind of cap 98 and forpurposes of accommodating various kinds and thicknesses of roof systems20, as particularly dictated by the number and kind(s) of insulationboards 30 employed and the kind and thickness of ballast materialemployed, with the rods 94 being made sufficiently long to accommodatesuch varied systems 20 and then potentially being trimmed or cut tolength as needed. More generally, it will again be appreciated that anysuch fastener assemblies 90 and related component designs now known orlater developed may be employed in the roof systems 20 according toaspects of the present invention without departing from its spirit andscope. It will be further appreciated that in any such arrangement asillustrated in FIG. 14C the fasteners 90 and netting 80 thus cooperateto secure the soil ballast 70 in place so as to prevent or minimizescour of the soil 70 for however long it takes to then install thevegetation mats 78 thereover as by effectively anchoring the soil 70within or beneath the one or more layers of insulation boards 30 andyielding an aggregate weight and wind uplift resistance. The arrangementshown in FIG. 14A being relatively temporary, as again awaitinginstallation of the overlying vegetation mat ballast material 78, thefastener rods 94 are thus left at their full length rather than beingtrimmed or cut off or otherwise supplied having sufficient length so asto extend beyond the soil 70 and netting 80 and eventually through thecoming vegetation mats 78. At this stage, other temporary ballastingmeasures can be taken as appropriate, such as placing sand bags (notshown) selectively about the roof system 20, which would then be removedwhen the final ballast system is applied. Accordingly, as then shown inFIG. 14D, when all inspections or other pre-ballast activities have beencompleted and the roof system 20 is to be finished, the additionallayer(s), here as illustrated in the “garden roof” context as beingvegetation mat ballast material 78, may be applied over thepreviously-installed membrane 50, one or more insulation boards 30, soil70, netting 80, and fastener assemblies 90. As such, the vegetation mat78 is simply laid over the soil 70 and pushed over the fasteners 90,namely, each rod 94 and first cap 98′, with a portion of the rod 94 thenprotruding beyond the netting 80 so as to accommodate an upper or secondcap 98″ placed over the vegetation mat 78, thereby completing the roofsystem 20, essentially in two steps performed some time apart while atall times satisfactorily securing or ballasting what layers of the roofsystem 20 have to that point been installed. Thus, it will beappreciated by those skilled in the art that the use of fasteners 90anchored in one or more layers of insulation boards 30 according toaspects of the present invention provides a convenient and effectivemulti-stage roof installation system as shown and described herein. Oncemore, it will be appreciated that a variety of other arrangements arepossible without departing from the spirit and scope of the invention,including utilizing different types and numbers of insulation boards andother layers and different types of ballast materials, such that theexemplary embodiments shown and described are to be understood asillustrative and non-limiting. Relatedly, and by way of furtherillustration and not limitation, while in the exemplary embodiment ofFIGS. 14C and 14D the resulting system 20 has a single netting 80located between the soil ballast material 70 and the vegetation matballast material 78, those skilled in the art will appreciate that asecond netting could be applied over the vegetation mat 78 as part ofthe second step of the ballast installation to further secure thevegetation mat 78 and thus the overall ballast system, as illustrated inFIG. 14B. Again, a virtually infinite variety of layers and arrangementsand related installation steps are possible according to aspects of thepresent invention.

Turning next to FIGS. 15-17C there are shown a variety of furtherexemplary embodiments of protected membrane roof systems 20 according toaspects of the present invention, here illustrated as perspective viewsanalogous to FIG. 1. As a threshold matter, while a particular exemplaryflat-roof building B with a parapet P of a particular arrangement isdepicted, it will be appreciated that a roof system 20 according toaspects of the invention, including but not limited to those exemplaryembodiments shown and described herein, may be employed in virtually anybuilding or roof context, and so is not in any way limited to thatillustrated. First, in FIG. 15, there is shown an exemplary “gardenroof” system 20 as installed on a building B, with such system 20spanning substantially the entire roof or region bounded by the parapetP, though it will be appreciated in any such context that there may beHVAC and other equipment (not shown) on the roof around which the system20 would be installed. As illustrated, a perimeter restraint for thesoil ballast 70 is provided as by having a width or section of netting80 around the border of the roof closest to the parapet P, with nonetting in the middle of the roof, which is simply exposed garden roof(soil and plants/vegetation). Here, then, substantially the entire roofsystem 20 is “garden roof,” with plants A both throughout the middle ofthe roof as coming up from the soil 70 and around the perimeter of theroof as coming up through the netting 80, again with only the perimeterbeing further restrained with the netting 80 and related below surfaceanchoring system or spaced-apart fasteners 90. Here, the fasteners 90are shown as being spaced relatively further apart, as compared with thespacing of FIG. 1, essentially along the outside and inside edges of thenetting 80. It will once again be appreciated that the anchoringfasteners 90 within the netting 80 along with the plants A would thuscooperate in securing the perimeter of the roof system 20 and preventingor reducing uplift or scatter of the soil ballast 70. More generally,those skilled in the art will appreciate that a variety of perimeterrestraint systems and methods, now known or later developed, may beemployed, in a variety of configurations, as will be further appreciatedwith reference to the alternative exemplary embodiments of FIGS. 16 and17A-17C, including but not limited to the use of netting 80 or not, theuse of other ballast materials as the perimeter restraint, and/or theuse of other perimeter restraint materials such as strapping S (FIGS.17B and 17C). It will also be appreciated that, as shown, a variety ofplants A suitable to the application and context may be incorporated inthe roof system 20, such that the appearance, number, and arrangement(location and spacing) of the plants A depicted in any and all of thefigures are to be understood as merely illustrative and non-limiting.Similarly, referring to FIG. 16, there is shown an alternative exemplaryembodiment of a “garden roof” system 20 again with a perimeter restraintincluding netting 80 with anchoring fasteners 90 located closest to theparapet P, though here shown as being relatively narrower than theperimeter netting 80 of FIG. 15. Moreover, it will be appreciated thatwhile a garden roof region with soil ballast 70 and plants A is shown inthe middle area of the roof bound by the perimeter netting 80, in thealternative embodiment of FIG. 16 the perimeter, rather than also being“garden roof” with soil ballast 70, may be configured having some otherballast material underneath the netting 80, such as a stone ballast 72as illustrated in FIG. 4 (again, in any such systems 20, the type,number, arrangement, and thickness of any related layers, including butnot limited to the number and characteristics of any insulation boards30, 40, are illustrative and non-limiting, as a variety of suchconfigurations are possible according to aspects of the presentinvention). It will be appreciated that with any such distinct perimeterrestraint, such as here where a heavier stone ballast 72 is usedrelative to the interior soil ballast 70, wind uplift resistance isthereby increased, with the size and arrangement of the netting 80 andthe spacing or density of the fasteners 90 further affectingperformance. More generally, as illustrated, in roof systems 20according to aspects of the present invention it will be appreciatedthat multiple kinds of ballast materials may be employed in a singlesystem 20 to suit a particular context. Those skilled in the art willthus appreciate that a variety of such features and combinations arepossible according to aspects of the present invention in seeking tooptimize the roof system 20 for a particular commercial application,whether from a cost stand-point, code-compliance stand-point, orgreenspace or other environmental stand-point, taking into considerationsuch factors as building design and weight or loading limits, type andamount of ballast to be used and related insulation board(s) and otherlayers in the system, parapet configuration, typical climate and windconditions, installation and maintenance costs, etc., such that any ofthe embodiments illustrated are again to be understood as illustrativeand non-limiting.

Referring particularly to FIGS. 17A-17C, then, there are shown stillfurther exemplary embodiments of protected membrane roof systems 20according to aspects of the present invention, here having a perimeterof pavers 74 (FIG. 17A) or panels 76 (FIG. 17B or 17C) closest to theparapet P, with the balance of the roof system 20 then inset from suchperimeter restraint region. First, in FIG. 17A, there is shown a “gardenroof” that is similar to that of FIG. 15, with a perimeter netting 80region anchored with spaced-apart fasteners 90 and having plants Atherein bounding a central region of soil ballast 70 also having plantsA, except that here the “garden roof” portion of the system 20 does notextend fully to the perimeter, or all the way to the parapet P of thebuilding B, but instead has a further perimeter restraint comprised herein the exemplary embodiment of two rows of pavers 74 anchored in theunderlying insulation boards as by using spaced-apart fasteners 90,though it will be appreciated that one row of pavers 74 or three or morerows may also be employed depending on a number of factors, with suchpavers and rows being of any desired geometry and potentially evenvarying around the perimeter. That is, it will be appreciated that inthe exemplary roof system 20 of FIG. 17A, there is a first perimeterrestraint system that may be characterized as a paver ballast sectionsuch as shown in FIGS. 11A and 11B (since no netting is shown as beingemployed over the pavers 74, though it will be appreciated that thenetting 80 could instead extend all the way to the parapet P and socover the perimeter portion of the “garden roof” region where a soilballast 70 is employed (both as exposed centrally and underneath thenetting 80) and the pavers 74, in which case the perimeter paver ballastsection could be represented by the exemplary arrangements shown inFIGS. 6 and 11C and 11D, it again being appreciated that a variety ofinsulation board and other layers may be employed beneath the ballastbeyond those shown and described). Moving inwardly there is shown asecond, inset perimeter restraint again configured here as a garden roofperimeter restrained as by the netting 80 and spaced-apart fasteners 90,such as illustrated in FIG. 10 (though no plants being shown there) orFIGS. 13A and 13B, recognizing that in any such “garden roof”arrangement soil 70 alone may be employed or growth media grids 82 intowhich the soil 70 and plants A are placed, or any other sucharrangement. It will be appreciated that the widths and arrangements ofsuch perimeter restraint regions may vary without departing from thespirit and scope of the invention, with other combinations alsopossible. For example, the interior netting-covered perimeter restraintof FIG. 17A shown as an extension of the central “garden roof” regionwith soil ballast 70 and plants A may instead comprise stone ballast 72as shown and described in connection with the perimeter restraintillustrated in FIG. 16 or any other such ballast material now known orlater developed. Once more, such ballast materials and relatedarrangements of their regions, in terms of their geometries andcharacteristics, may be combined in a variety of ways according toaspects of the present invention beyond those shown and described, suchexemplary embodiments then being understood as illustrative andnon-limiting. Relatedly, once more, the fastener spacing or density mayalso vary widely depending on the context. In FIG. 17B, then, there isshown yet another “garden roof” arrangement of the system 20 similar tothat of FIG. 17A, particularly as to the central region with the soilballast 70 and perimeter netting 80 and spaced-apart fasteners 90 withplants A throughout, though here having a different outer perimeterrestraint closest to the parapet P configured as a layer ofrectangular-shaped insulation panels 76 further restrained withstrapping S. As for the insulation panels 76 themselves, they may herecover just the perimeter portion of the roof and, whether or notinterlocking or including any other fastening or restraint system asherein described, may also include a system of strapping S, such asmetal strips laying over such panels 76 lengthwise and being staked toeach other and/or to the parapet P or other roof structure toeffectively “tie down” the ballast material here as perimeter insulationpanels 76. By way of illustration and not limitation, such strapping Smay be configured or arranged as supplied and/or specified by T ClearCorporation in Hamilton, Ohio as its “System 1”, “System 2” or “System3” “Wind Designs & Securement for T. Clear Protected Membrane RoofSystems Using Lightguard® or Heavyguard® Ballasts,” though it will beappreciated that a variety of perimeter restraint systems for winddesign or otherwise from a variety of sources may be employed inconjunction with aspects of the present invention, it being appreciatedthat any such third-party restraint system is thereby enhanced by virtueof the added or improved wind uplift resistance characteristics of roofsystems 20 according to aspects of the present invention, with suchperimeter restraint systems able to be reduced in cost and complexityfor the substantially the same performance or to perform relativelygreater at the same cost and complexity. Accordingly, once more, it willbe appreciated that a variety of arrangements and combinations offeatures according to aspects of the present invention are possiblewithout departing from its spirit and scope. Similarly, as shown in FIG.17C, effectively the same perimeter restraint arrangement with ballastinsulation panels 76 may be employed as illustrated, including restraintstrapping S, only here with the central portion of the roof alsocomprising such insulation panels 76 as the ballast, rather than a“garden roof” area with soil ballast 70, as seen via the centralcut-away area in FIG. 17C, such central panels 76 further shown as beingcovered by a netting 80 anchored by spaced-apart fasteners 90 seatedwithin the at least one insulation board 30 as shown by way of examplein FIGS. 7 and 12B (since netting 80 is employed, though in a furtheralternative embodiment netting may not be employed and the panels 76still anchored via fasteners 90 as illustrated in FIG. 12A), again, anycombination of such features and layers, including but not limited tothe number and arrangement of any underlying insulation boards and thuswhat board(s) the fasteners 90 are anchored in, are possible accordingto aspects of the present invention without departing from its spiritand scope. Once more, any fastener spacing or density is also possibledepending on the context as explained herein. In the exemplaryembodiment of FIG. 17C, though again not being to scale or to be takenas such or as conveying any dimensional information, by way ofillustration and not limitation, the fasteners 90 throughout the netting80 in the central portion of the roof may be positioned as one per“square,” or one per each one hundred square feet (100 sq. ft.) or tenfoot by ten foot (10′×10′) area, putting such fasteners 90 essentiallyat a spacing of ten feet (10′) on center in both directions, thoughagain it will be appreciated that a virtually infinite range of spacingsor fastener densities may be employed. Indeed, by way of furtherillustration and not limitation, in another arrangement a twenty foot bytwenty foot (20′×20′) area encompassing four hundred square feet (400sq. ft.) is considered the applicable area, with one fastener 90 at eachcorner of that 20′×20′ area yielding four fasteners per 400 sq. ft. orone for every 100 sq. ft. (or one per “square”), here with the fasteners90 thus at a spacing of twenty feet (20′) on center in both directions.Moreover, the spacing may be uniform throughout all or part of the roofor may be at varied spacing, such as having closer spacing or greaterfastener density at the perimeter restraint areas or along nettingseams, for example. More generally, it will be appreciated that wherethe netting 80 meets any perimeter restraint system, whether employingpavers 74 (FIGS. 1 and 17A) or insulation panels 76 (FIGS. 17B and 17C),alone or in any combination and at any width or other configuration andwith or without any strapping S or other perimeter restraint hardware,such netting 80 may be tucked in or staked or otherwise secured undersuch perimeter restraint system to further anchor the netting 80 alongwith any fasteners 90 employed.

Finally, referring to FIGS. 18A and 18B there is shown yet anotheralternative exemplary embodiment protected membrane roof system 20according to aspects of the present invention, here illustrated as beinginstalled in two stages or steps or operational modes. First, asillustrated in FIG. 18A, an initial or immediate step or mode entailsinstalling one or more layers of insulation boards 30, 40 over thewaterproofing membrane 50 as called for in the commercial context, againbased on a number of variables, here two such boards 30, 40 beingillustrated. Fastener assemblies 90 are spaced along and installedthrough holes formed in the upper insulation board 30 as by having thebase 92 of each fastener 90 positioned beneath and adjacent to the upperinsulation board 30 and the rods 94 extend up through the upper boards30. Once more, actual fastener spacing can vary, such that theillustrated embodiment of FIGS. 18A and 18B is to be understood asexemplary and non-limiting and not taken literally or to scale. A firstnetting 80′ is laid or stretched across the upper insulation boards 30,whether before or after the fasteners 90 are placed, with first caps 98′then threadably or otherwise secured on or about the rods 94 so as tosecure the first netting 80′ over the layer of upper insulation boards30. Where the first cap 98′ is to be threadably engaged with the rod 94,it will be appreciated that the threaded portion 96 of the rod 94 maythus extend substantially along its entire length, or at least along agreater and/or lower section of its length; it will also be appreciatedthat such first cap 98′ is to have a through-hole allowing for completepassage therethrough of the rod 94, while the second cap 98″ asdescribed further below and consistent with the caps 98 shown generallyin the other exemplary embodiments need not necessarily have athrough-hole, though still might, both for the sake of convenience interms of inventorying only kind of cap 98 and for purposes ofaccommodating various kinds and thicknesses of roof systems 20, asparticularly dictated by the number and kind(s) of insulation boards 30,40 employed and the kind and thickness of ballast material employed,with the rods 94 being made sufficiently long to accommodate such variedsystems 20 and then being trimmed or cut to length as needed. Moregenerally, it will be appreciated that any such fastener assemblies 90and related component designs now known or later developed may beemployed in the roof systems 20 according to aspects of the presentinvention without departing from its spirit and scope. It will befurther appreciated that in any such arrangement as illustrated in FIG.18A the fasteners 90 and netting 80 thus cooperate to further secure theupper insulation boards 30 in place as by effectively tying themtogether as a collective system having an aggregate weight and winduplift resistance. This being a relatively temporary arrangement, suchas to allow time for inspection and/or the “permanent” ballasting step,the fastener rods 94 are thus left at their full length rather thanbeing trimmed or cut off. At this stage, other temporary ballastingmeasures can be taken as appropriate, such as placing sand bags (notshown) selectively about the roof system 20, which would then be removedwhen the final ballast system is applied. Accordingly, as then shown inFIG. 18B, when all inspections or other pre-ballast activities have beencompleted and the roof system 20 is to be finished, the additionallayers, here as illustrated in the “garden roof” context, may be appliedover the previously-installed membrane 50, one or more insulation boards30, 40, first netting 80′, and fastener assemblies 90—namely, continuingfrom bottom to top, a drainage retention layer 60, a filter fabric layer62, soil ballast 70 (again, with or without any growth media grids 82(FIGS. 13A and 13B)), and a second netting 80″ capped and held in placeby upper or second caps 98″ placed over the upper or second netting 80″and installed on the respective fastener rods 94, thereby completing theroof system 20, essentially in two steps performed some time apart whileat all times satisfactorily securing or ballasting what layers of theroof system 20 have to that point been installed. Thus, it will beappreciated by those skilled in the art that the use of fasteners 90anchored in one or more layers of insulation boards 30, 40 according toaspects of the present invention provides a convenient and effectivemulti-stage roof installation system as shown and described herein. Oncemore, it will be appreciated that a variety of other arrangements arepossible without departing from the spirit and scope of the invention,including utilizing different types and numbers of insulation boards andother layers and different types of ballast materials, such as stone 72,pavers 74, or panels 76, such that the exemplary embodiments shown anddescribed are to be understood as illustrative and non-limiting.

To summarize, regarding the exemplary embodiments of the presentinvention as shown and described herein, it will be appreciated that aprotected membrane roof system is disclosed and configured foreffectively anchoring a netting positioned over a ballast materialand/or a ballast material itself beneath an upper insulation boardpositioned beneath the ballast material. Because the principles of theinvention may be practiced in a number of configurations beyond thoseshown and described, it is to be understood that the invention is not inany way limited by the exemplary embodiments, but is instead able totake numerous forms to do so without departing from the spirit and scopeof the invention. It will also be appreciated by those skilled in theart that the present invention is not limited to the particulargeometries and materials of construction disclosed, but may insteadentail other functionally comparable structures or materials, now knownor later developed, without departing from the spirit and scope of theinvention. Furthermore, the various features of each of theabove-described embodiments may be combined in any logical manner andare intended to be included within the scope of the present invention.

While aspects of the invention have been described with reference to atleast one exemplary embodiment, it is to be clearly understood by thoseskilled in the art that the invention is not limited thereto. Rather,the scope of the invention is to be interpreted only in conjunction withthe appended claims and it is made clear, here, that the inventor(s)believe that the claimed subject matter is the invention.

1. A protected membrane roof system for installation on a roof decking,comprising: an upper insulation board having an upwardly-facing upperboard top surface and an opposite downwardly-facing upper board bottomsurface, the upper insulation board positioned over and in closeproximity to the roof decking; a lower insulation board having anupwardly-facing lower board top surface and an oppositedownwardly-facing lower board bottom surface, the lower insulation boardpositioned beneath the upper insulation board, between the upperinsulation board and the roof decking, such that the upper board bottomsurface is immediately adjacent the lower board top surface; a ballastmaterial positioned over and in close proximity to the upper insulationboard; at least one fastener assembly configured to restrain the ballastmaterial and comprising a base positioned immediately adjacent the lowerboard bottom surface; and a waterproof membrane positioned over and inclose proximity to the roof decking beneath and in close proximity tothe upper insulation board, the at least one fastener assembly neitherpenetrating nor attaching to the waterproof membrane; whereby the winduplift resistance of the protected membrane roof system is improved andscour of the ballast material is reduced by effectively anchoring theballast material beneath both the upper and lower insulation boardspositioned beneath the ballast material.
 2. The system of claim 1further comprising a netting positioned over at least a portion of theballast material, the at least one fastener assembly configured toselectively engage the netting, whereby the netting is anchored beneathboth the upper and lower insulation boards positioned beneath theballast material without compromising the waterproof membrane.
 3. Thesystem of claim 2 wherein the netting and the ballast material extend toa perimeter of the roof decking.
 4. The system of claim 1 wherein the atleast one fastener assembly further comprises a rod extendingsubstantially vertically from the base of sufficient size so as toextend beyond the upper and lower insulation boards and through theballast material.
 5. The system of claim 1 wherein the ballast materialis soil.
 6. The system of claim 5 further comprising a plurality ofgrowth media grids containing at least a portion of the soil ballastmaterial and positioned above and in close proximity to the upperinsulation board, the plurality of growth media grids providing furtherperimeter restraint and wind uplift resistance of the protected membraneroof system.
 7. The system of claim 6 wherein the at least one fastenerassembly passes through at least one of the plurality of growth mediagrids.
 8. The system of claim 7 further comprising a netting positionedover at least the plurality of growth media grids containing the soilballast material, the at least one fastener assembly configured toselectively engage the netting, whereby the netting is anchored beneathboth the upper and lower insulation boards positioned beneath theplurality of growth media grids containing the soil ballast material. 9.The system of claim 1 further comprising a plurality of pavers orinsulation panels adjacent to the ballast material and the upperinsulation board, the pavers or insulation panels providing furtherperimeter restraint and wind uplift resistance of the protected membraneroof system.
 10. The system of claim 9 wherein the at least one fastenerassembly passes through at least one of the pavers or insulation panels.11. The system of claim 9 further comprising a netting positioned overat least a portion of the ballast material, the at least one fastenerassembly configured to selectively engage the netting, whereby thenetting is anchored beneath both the upper and lower insulation boardspositioned beneath the ballast material and the netting is furtheranchored about its perimeter by the plurality of pavers or insulationpanels.
 12. The system of claim 1 wherein the ballast material isinsulation panels.
 13. The system of claim 12 wherein the insulationpanels are concrete-faced foam.
 14. The system of claim 1 wherein theballast material is pre-cultivated vegetation mat installed over soil.15. The system of claim 14 further comprising a netting positioned overthe vegetation mat, the at least one fastener assembly configured toselectively engage the netting, whereby the netting is anchored beneathboth the upper and lower insulation boards positioned beneath the soiland vegetation mat ballast material.
 16. The system of claim 14 furthercomprising a netting positioned over the soil, the at least one fastenerassembly configured to selectively engage the netting and to extendbeyond the netting and through the vegetation mat, whereby the nettingand the vegetation mat are anchored beneath both the upper and lowerinsulation boards positioned beneath the soil and vegetation mat ballastmaterial.
 17. (canceled)
 18. (canceled)
 19. (canceled)
 20. (canceled)21. The system of claim 1 comprising at least two lower insulationboards defining at least a first lower insulation board positioned overthe waterproof membrane and a second lower insulation board positionedover the first lower insulation board between the first lower insulationboard and the upper insulation board, wherein the base of the fastenerassembly is positioned beneath the second lower insulation board betweenthe second lower insulation board and the first lower insulation board,whereby the base of the fastener assembly is separated from thewaterproof membrane by at least the first lower insulation board.
 22. Aprotected membrane roof system for installation on a roof decking,comprising: an upper insulation board having an upwardly-facing upperboard top surface and an opposite downwardly-facing upper board bottomsurface, the upper insulation board positioned over and in closeproximity to the roof decking; a waterproof membrane positioned over andin close proximity to the roof decking beneath and in close proximity tothe upper insulation board; at least two lower insulation boardsdefining at least a first lower insulation board positioned over thewaterproof membrane and a second lower insulation board positioned overthe first lower insulation board between the first lower insulationboard and the upper insulation board; a ballast material positioned overand in close proximity to the upper insulation board; and at least onefastener assembly comprising a base positioned beneath at least thesecond lower insulation board and configured to restrain the ballastmaterial; whereby the wind uplift resistance of the protected membraneroof system is improved and scour of the ballast material is reduced byeffectively anchoring the ballast material beneath at least the upperinsulation board and one or more lower insulation board positionedbeneath the ballast material, and further whereby the at least onefastener assembly neither penetrates nor attaches to the waterproofmembrane as by the waterproof membrane being separated from the base ofthe fastener assembly by at least the first lower insulation board. 23.(canceled)
 24. A protected membrane roof system for installation on aroof decking, comprising: a plurality of upper insulation boards eachhaving an upwardly-facing upper board top surface and an oppositedownwardly-facing upper board bottom surface, the upper insulationboards positioned over and in close proximity to the roof decking andsubstantially covering the roof decking to a perimeter thereof; aballast material positioned over and in close proximity to at least aportion of the upper insulation boards; a plurality of pavers orinsulation panels adjacent to the ballast material and the upperinsulation boards substantially at the perimeter of the roof decking; atleast one fastener assembly each having a base seated beneath one of theplurality of upper insulation boards and configured to restrain at leastone of the ballast material and the plurality of pavers or insulationpanels; a netting positioned over at least a portion of the ballastmaterial, the at least one fastener assembly configured to selectivelyengage the netting; and a waterproof membrane positioned over and inclose proximity to the roof decking beneath and in close proximity tothe upper insulation board, the at least one fastener assembly neitherpenetrating nor attaching to the waterproof membrane; whereby the winduplift resistance of the protected membrane roof system is improved andscour of the ballast material is reduced by effectively anchoring thenetting beneath at least the upper insulation board positioned beneaththe ballast material and further anchoring the netting about itsperimeter by the plurality of pavers or insulation panels.
 25. Aprotected membrane roof system for installation on a roof decking,comprising: an upper insulation board having an upwardly-facing upperboard top surface and an opposite downwardly-facing upper board bottomsurface, the upper insulation board positioned over and in closeproximity to the roof decking; a lower insulation board having anupwardly-facing lower board top surface and an oppositedownwardly-facing lower board bottom surface, the lower insulation boardpositioned beneath the upper insulation board, between the upperinsulation board and the roof decking; a ballast material positionedover and in close proximity to the upper insulation board; at least onefastener assembly configured to restrain the ballast material andcomprising a base positioned beneath the upper insulation board, thebase of the fastener assembly being adjacent to the upper board bottomsurface; and a waterproof membrane positioned over and in closeproximity to the roof decking beneath and in close proximity to theupper and lower insulation boards, whereby the base of the fastenerassembly is separated from the waterproof membrane by at least the lowerinsulation board such that the at least one fastener assembly neitherpenetrates nor attaches to the waterproof membrane; whereby the winduplift resistance of the protected membrane roof system is improved andscour of the ballast material is reduced by effectively anchoring theballast material beneath at least the upper insulation board positionedbeneath the ballast material.